1. Field of the Invention
The invention relates to communication methods and systems, and more precisely, to methods and systems for communicating with a mobile node with multiple interfaces in a heterogeneous radio network.
2. Description of the Related Art
In recent years, mobile nodes (MN) with multiple wireless interfaces operated in heterogeneous overlay wireless networks have become increasingly popular. In a heterogeneous overlay wireless network, an MN can activate multiple interfaces simultaneously to gain permanent and ubiquitous access to the Internet, and to improve connectivity, reliability, and throughput following access to the Internet. In this scenario, an MN may have multiple unique IP addresses in an all-IP network, such as an IPv6 network. To allow correspondent nodes (CNs) to always be able to connect to an MN through any MN's IP address, the MN must keep its interfaces active to avoid packet loss.
For an MN, especially a battery-operated device with multiple wireless interfaces, power consumption is one of the critical issues. One possible solution for conserving power is to set interfaces to power-saving modes when no packets are to be sent or received. This solution, however, forces power consumption of an MN with multiple interfaces to increase substantially, even when interfaces are idle.
Alternatively, when no packets are to be sent or received, an MN can turn off the wireless interfaces completely; however, packets sent to the IP addresses associated with these turned-off interfaces of the MN will be lost.